Synthetic lubricant composition



Patented Aug. 30,- 1960 SYNTIETHC LUBRICANT CONHOSITION Charles E. annders, Silver Spring, Md, assignor to the United States of America as represented by the Secretary of the Navy N Drawing. Filed Aug. 9, 1956, Ser. No. 603,197

6 Claims. or. 252-341 (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to synthetic lubricants and additives therefor. More particularly the invention relates to water soluble polymerized alkylene oxide oils and to additives which improve the lubricity and antioxidant characteristics of these oils so as to make them useful under extreme ambient conditions while retaining their water soluble characteristics.

This application is a continuation-in-part of Serial No. 241,380, filed August 10, 1951, now abandoned.

Improved high powered turbine type internal combustion engines have recently been developed for use in high speed underwater ordnance equipment such as submarines and torpedoes. An example of this type of engine is the hydrogen peroxide propelled engine used in submarines. This engine is combined with the conventional diesel engine with the peroxide reserved for special bursts of speed in attacking and escaping. Free oxygen combines with fuel such as diesel oil to produce the steam and carbon dioxide to drive the turbine under ordinary circumstances. When high speed is desired the hydrogen peroxide is utilized as the fuel. The hydrogen peroxide breaks down to provide the heat used as the source of energy. The principal advantage of the use of hydrogen peroxide is that no exhaust bubbles reach the surface, thus adding a safety factor to the submarines operation. The hydrogen peroxide engine, however, develops temperatures in the nature of 1200 P. so that it is highly desirable to utilize sea water as a coolant. The sea water so used tends to wash away the lubricants employed in the engine and such lubricants are discharged with the sea water. Ordinary lubricants being insoluble in sea water tend to form a wake in the form of an oil slick which rises to the surface. The presence of this slick may be detected by surface craft and the advantage obtained by the submarine through the use of the hydrogen peroxide engine is largely overcome. In addition, ordinary lubricants tend to wash off the engine parts in the presence of sea water. They also are extremely corrosive and breakdown in the presence of the steam and free oxygen employed in the engines.

Many mineral oils, compounded heavy duty oils and synthetic oils have been extensively tested in an efiort to eliminate this slick type of wake while retaining the necessary high lubricity and anticorrosive characteristics required for use in the engines of the hydrogen peroxide type. The results of these tests showed that to perform as required a lubricant must be either water soluble or have a specific gravity considerably greater than that of sea water. These characteristics must be retained even after the lubricant has been subjected to the rigors of the high temperatures developed in the combustion chamber of hydrogen peroxide engines or the like.

index, pour point and sludge formation. However, these I alkylene oxide oils have been found to give inadequate lubrication under the conditions of operation described for the hydrogen peroxide engine and have been found to be unduly corrosive when compared to hydrocarbon oils.

Attempts to improve the lubricity and anticorrosive characteristics of the polymerized alkylene oxide oils while retaining their water soluble, slick free qualities have not heretofore been successful. All previously known additives either do not improve the lubricity and anticorrosive characteristics of the alkylene oxide oils or result in the lubricants forming the highly undesirable slicks.

It is, therefore, an object of the present invention to provide a new and improved additive for use with alkylene oxide oils.

Another object is to provide a new and improved alkylene oxide lubricating compound having improved lubricity and anticorrosive characteristics.

A further object is to provide a new and improved lubricating composition which is soluble in water and will not form a slick when used under water.

A still further object is to provide an additive for improving the lubricity qualities of alkylene oxide oils while decreasing their corrosiveness.

Other objects and the attendant advantages of the invention will be apparent to those skilled in the art as the invention is disclosed in the following detailed description.

The objects of the present invention are achieved by the addition to the alkylene oxide oil of a small proportion of a compound selected from a class of compounds prepared by the reaction of monoethanolamine, diethanolamine or tn'ethanolamine with an organic acid containing from 8-20 carbon atoms. It has been found that the addition to an alkylene oxide oil of even as small a percentage of one of these compounds as 0.2 to 5.0 percent permits satisfactory lubrication of an internal combustion engine even when 50 percent of sea water is present in the crankcase of the engine. The addition of this small proportion of one of these compounds permits the use of the water soluble alkylene oxide oils as lubricants in steam cylinders and the like at high temperatures without the production of water insoluble byproducts.

The additives of the present invention may be prepared by reacting monoethanolamine, diethanolamine or triethanolamine with an organic aliphatic acid containing from 820 carbon atoms. The aliphatic acids used for this purpose may be saturated or unsaturated, normal or forked. The acids found best for this purpose were those of higher carbon content such as oleic acid (C17H33COOH), stearic acid (C17H35'COOH), acid ('C H COOH), recinoleic acid (CH (CH CHOHCH=CH (CH COOH) The preferred additive is the compound prepared by the reaction of tn'ethanolamine with oleic acid i.e. triethanolamine oleate.

H 01111330ooH+N(cHrOmoH)a onHno001 I-(o112o1120'H)r (oleic acid) (triethanolamine) (triethanolamine oleate):

The alkylene oxide oils used in the lubricating composition of theinvention are the oils composed of the water soluble polymerized ethylene glycols and derivatives thereof. These oils are commercially available under the trade name Ucon Lubricants from the Carbide and Car: bon Chemicals Company. Only the water soluble oils are useful in the composition of this invention, however; Ucon HB series lubricants are water soluble oils madeby copolymerizing a mixture of ethylene oxide (C H O) and propylene oxide (C H O). 'These oils, being water soluble, form no slick on the surface of water. They do not carbonize in the engine as badly as petroleum oils but are depolymeri zed forming water soluble glycols, acids and aldehydes leaving an exceptionally clean engine. These oils may be polymerized to any desired viscosity. Of the Ucon I-IB series lubricants Ucon 501-13 660 is the preferred lubricant. This oil is prepared by copolymeriziug a 50-50 mixture of ethylene oxide and propylene oxide. As commercially available Ucon OI-IB660 has the following properties:

Viscosity SSU at:

No particular conditions are required for the preparation of the lubricating composition. The additive is prepared by a reaction which takes place at room temperature. The amine is merely mixed with the acid with stirring. The additives may be prepared prior to mixing.

with the alkylene oxide oils by mixing stoichiometric quantities of the reactants or alternatively the additives may be formed in situ by mixing the reactants in the proportions recited directly in the alkylene oxide oil at room temperature.

The following example is given by way of illustration and is not to be construed as limiting the invention in any manner.

Example 1 A sample was prepared by reacting 409 gms. of triethanolamine and 387 gms. of oleic acid and diluting the resulting triethanolamine oleate with Ucon 50-HB660 to bring the mixture up to 87.9 lbs. at EES. This is equivalent to a 2.0% solution :in the Ucon- 504-113-660.

The sample was tested for the formation of an oil slick on a one cylinder, four stroke cycle, Lauson gaso line engine so modified as to give a condition of excessive oil consumption. For this purpose the oil-control ring was removed from the piston leaving'only the two compression rings. A mixture of hydrogen, oxygen and steam was used as the fuel. The exhaust from the engine was piped to the lowest point of .a tankholding 15 gals. of seat water about four feet deep. A baffle plate with small holes was placed above the exhaust line to; distribute the gases throughout the tank area.

Straight mineral oils and compounded heavy duty oils formed objectionable oil slicks onthesurface of the waterv with the above tests. Various synthetic oils were. also tested including glycerin, tricresyl phosphate, Hydrolubes;

'Ucon LB series, Arochlor 1278, Gulf OECA and Dow Corning FluidsNo. 200, No. 710 and No. 500. All the oils tested gave unsatisfactory results except. the Ucon. HB series. Theoils of this series did not produce a slick and the sample of Ucon 50 HB 660 with the 2.0% of triethanolamine oleate added was tested; all the products of the exhaust were found to be soluble and left no slick on the surface.

The mixture of Ucon 50 HB 660 and triethanolamine oleate was tested for comparison with other lubricants on a wear test machine. The testing machine was a constant speed'(1800 r.p.m;) motor with a hardened steel wheel attached to .the shaft. This wheel was hardened to Rockwell 60c. The motor was attached to a base plate which held a lever arrangement that permitted loading of the test piece.

The test pieces'were cold rolled steel A2" x 2'? x 7 The loading was accomplished by using the lever arrangement to force the test piece against the wheel. A'5zl lever ratio gave-a 20 pound loading at the point of contact. The tested lubricant was fed from a drip oiler so it just contacted the. edge of the wheel as it was fed.

The test was started by allowing the oil to completely cover the sample and to flow at an arbitrary drip rate (about 90 drops per minute) which was maintained for the duration of the run. come into contact with the wheel and the test was allowed to runfor 5 'minutes. The test was secured by removing the sample from contact with the wheel. The resultant length of the mark on the test sample served as a comparative measurement of the quality of the lubricant tested. a t

A petroleum base oil SAE 30 blended with 20 percent I 50 percent sea wateim Y The' results of the water test showed that the Ucon 50 HB 660 plus 2% triethanolamine oleate mixture had better lubricating qualities than the standard petroleum base oil and showed a reduction of over 50 percent of wear over the Ucon. 50 HB 660 without additive.

The Ucon 50 HB 660 triethanolamine oleate mixture was subjected to a storage test and was found not to separate out after 6 mos. at 150 F. The anticorrosive qualities of.the mixture were also tested and found to be satisfactory over a period of several weeks.

From the foregoing it may be seen that there has been provided a new anduseful additive for water soluble alkyleneoxide lubricants which renders. those oils comparable to or better than the bestpetroleum oils when mixed with up to 50 percent sea water. The resulting lubricant composition is soluble in sea water and remains so after being 'subjected to the rigors of the high temperatures of the combustion ,chamber'of an internal com bustion engine and accordingly forms'no' undesirable slick on the surface of the water.

This improved lubricating composition composed of.

copolymerized ethylene oxide and propylene oxide with up to 5% of triethanolamine oleate hasbeen employed successfullywith no corrosive results and with no slick forming effects in engines of the hydrogen peroxide type intorpedoes and submarines.

7 Obviously many. modifications and variations of the What is claimed as'new and desired to be secured by Letters Patent of the United Statesis v 1. A water soluble lubricating composition consisting essentially of :a water soluble alkylene oxide oil of The sample was allowed to.

copolymerized ethylene oxide and propylene oxide, and from 0.2 to 5.0 percent by weight of triethanolamine oleate.

2. A water soluble lubricating composition consisting essentially of a water soluble alkylene oxide oil of copolymerized ethylene oxide and propylene oxide, and from 0.2 to 5.0 percent by Weight of an additive selected from the group consisting of mono-, diand triethanolamine oleate.

3. A water soluble lubricating composition consisting essentially of a water soluble alkylene oxide oil of copolymerized ethylene oxide and propylene oxide, and from 0.2 to 5.0 percent by Weight of an additive selected from the group consisting of the mono-, diand triethanolamine salts of an aliphatic acid having from 8 to 20 carbon atoms.

4. A water soluble lubricating composition consisting essentially of a water soluble polymerized alkylene oxide oil substantially half of which is ethylene oxide and half propylene oxide, and from 0.2 to 5.0 percent by weight of an additive selected from the group consisting of the mono-, diand triethanolamine salts of an aliphatic acid having from 8 to 20 carbon atoms.

5. The lubricating composition of claim 4 in which the acid is oleic acid.

6. The lubricating composition of claim 4 in which the additive is triethanolamine oleate.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Ucon, Carbide and Carbon Chem. Corp., New York (1948), Table 3, between pages 10 and 11. 

3. A WATER SOLUBLE LUBRICATING COMPOSITION CONSISTING ESSENTIALLY OF A WATER SOLUBLE ALKYLENE OXIDE OIL OF COPOLYMERIZED ETHYLENE OXIDE AND PROPYLENE OXIDE, AND FROM 0.2 TO 5.0 PERCENT BY WEIGHT OF AN ADDITIVE SELECTED FROM THE GROUP CONSISTING OF THE MONO, DI AND TRIETHANOLAMINE SALTS OF AN ALIPHATIC ACID HAVING FROM 8 TO 20 CARBON ATOMS. 